Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO-Houssay), Grupo de Neurociencia de Sistemas, Universidad de Buenos Aires y Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, 1121, Argentina.
Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO-Houssay), Grupo de Neurociencia de Sistemas, Universidad de Buenos Aires y Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, 1121, Argentina
J Neurosci. 2020 Apr 15;40(16):3304-3317. doi: 10.1523/JNEUROSCI.1897-19.2020. Epub 2020 Mar 23.
Although the etiology of schizophrenia is still unknown, it is accepted to be a neurodevelopmental disorder that results from the interaction of genetic vulnerabilities and environmental insults. Although schizophrenia's pathophysiology is still unclear, postmortem studies point toward a dysfunction of cortical interneurons as a central element. It has been suggested that alterations in parvalbumin-positive interneurons in schizophrenia are the consequence of a deficient signaling through NMDARs. Animal studies demonstrated that early postnatal ablation of the NMDAR in corticolimbic interneurons induces neurobiochemical, physiological, behavioral, and epidemiological phenotypes related to schizophrenia. Notably, the behavioral abnormalities emerge only after animals complete their maturation during adolescence and are absent if the NMDAR is deleted during adulthood. This suggests that interneuron dysfunction must interact with development to impact on behavior. Here, we assess how an early NMDAR ablation in corticolimbic interneurons impacts on mPFC and ventral hippocampus functional connectivity before and after adolescence. In juvenile male mice, NMDAR ablation results in several pathophysiological traits, including increased cortical activity and decreased entrainment to local gamma and distal hippocampal theta rhythms. In addition, adult male KO mice showed reduced ventral hippocampus-mPFC-evoked potentials and an augmented low-frequency stimulation LTD of the pathway, suggesting that there is a functional disconnection between both structures in adult KO mice. Our results demonstrate that early genetic abnormalities in interneurons can interact with postnatal development during adolescence, triggering pathophysiological mechanisms related to schizophrenia that exceed those caused by NMDAR interneuron hypofunction alone. NMDAR hypofunction in cortical interneurons has been linked to schizophrenia pathophysiology. How a dysfunction of GABAergic cortical interneurons interacts with maturation during adolescence has not been clarified yet. Here, we demonstrate that early postnatal ablation of the NMDAR in corticolimbic interneurons results in an overactive but desynchronized PFC before adolescence. Final postnatal maturation during this stage outspreads the impact of the genetic manipulation toward a functional disconnection of the ventral hippocampal-prefrontal pathway, probably as a consequence of an exacerbated propensity toward hippocampal-evoked depotentiation plasticity. Our results demonstrate a complex interaction between genetic and developmental factors affecting cortical interneurons and PFC function.
虽然精神分裂症的病因仍然未知,但它被认为是一种神经发育障碍,是由遗传易感性和环境损伤相互作用引起的。虽然精神分裂症的病理生理学仍然不清楚,但尸检研究表明皮质中间神经元的功能障碍是一个核心要素。有人认为,精神分裂症中副甲状腺素阳性中间神经元的改变是由于 NMDAR 信号转导不足所致。动物研究表明,皮质边缘中间神经元中 NMDA 受体的早期产后消融会导致与精神分裂症相关的神经生化、生理、行为和流行病学表型。值得注意的是,只有在动物完成青春期成熟后,行为异常才会出现,如果在成年期删除 NMDA 受体,则行为异常不存在。这表明中间神经元功能障碍必须与发育相互作用才能影响行为。在这里,我们评估了皮质边缘中间神经元中早期 NMDA 受体消融对青春期前后 mPFC 和腹侧海马功能连接的影响。在幼年雄性小鼠中,NMDA 受体消融导致多种病理生理特征,包括皮质活动增加和局部γ节律和远端海马θ节律的同步性降低。此外,成年雄性 KO 小鼠显示出较低的腹侧海马- mPFC 诱发电位和增强的低频刺激 LTD 通路,表明成年 KO 小鼠这两个结构之间存在功能连接中断。我们的结果表明,中间神经元中的早期遗传异常可以与青春期后的出生后发育相互作用,触发与精神分裂症相关的病理生理机制,这些机制超过了 NMDA 受体中间神经元功能低下单独引起的机制。NMDAR 功能低下在皮质中间神经元中与精神分裂症的病理生理学有关。GABA 能皮质中间神经元的功能障碍如何与青春期的成熟相互作用尚未阐明。在这里,我们证明了皮质边缘中间神经元中 NMDA 受体的早期产后消融会导致青春期前 PFC 过度活跃但不同步。在这个阶段的最终产后成熟扩大了遗传操作的影响,导致腹侧海马-前额叶通路的功能连接中断,可能是由于海马诱发去极化可塑性的加剧倾向所致。我们的结果表明,影响皮质中间神经元和 PFC 功能的遗传和发育因素之间存在复杂的相互作用。